There has been a demand to accelerate image data conversion through the use of the error diffusion method. To convert image data, it is determined whether a specified block process condition is satisfied on the basis of a gradation value for each pixel in a target block. When the block process condition is true, a process is performed to diffuse a gradation error for the entire target block and convert image data for pixels in the target block at a time. Even when the block process condition is false, it is determined whether to form a dot in the target block. When it is determined that no dot should be formed, a process is performed to diffuse a gradation error for the entire target block to the unconverted pixels in another block and convert image data for pixels in the target block.
Legal claims defining the scope of protection, as filed with the USPTO.
1. An image data processing apparatus which inputs image data generated from an image represented in multiple gradations of dot matrix pixels, diffuses a gradation error for each pixel to the other unconverted pixels, and converts the input image data to image data represented by presence or absence of dot formation, the apparatus comprising: a block process determination unit for forming a block by grouping a specified number of neighboring pixels and determining whether or not a specified block process condition is satisfied on the basis of a gradation value for each pixel in a target block to convert the image data; a first conversion unit for diffusing a gradation error for the entire target block to unconverted pixels outside the target block on the basis of the gradation value and the diffused gradation error for each pixel in the target block and converting image data for pixels in the target block at a time when the block process determination unit determines the block process condition to be true; and a second conversion unit for determining whether or not to form a dot in the target block on the basis of the gradation value and the diffused gradation error for each pixel in the target block when the block process determination unit determines the block process condition to be false, for converting image data for pixels in the target block while diffusing a gradation error for the pixel partition to the other unconverted pixels on the basis of the gradation value and the diffused gradation error for each pixel according to each pixel partition comprising grouped pixels in the target block when it is determined that a dot is to be formed in the target block, and for converting image data for pixels in the target block at a time while diffusing a gradation error for the entire target block to the other unconverted pixels outside the target block on the basis of the gradation value and the diffused gradation error for each pixel in the target block when it is determined that no dot is to be formed in the target block.
2. An image data processing method which inputs image data generated from an image represented in multiple gradations of dot matrix pixels, diffuses a gradation error for each pixel to the other unconverted pixels, and converts the input image data to image data represented by presence or absence of dot formation, the apparatus comprising: a block process determination step of forming a block by grouping a specified number of neighboring pixels and determining whether or not a specified block process condition is satisfied on the basis of a gradation value for each pixel in a target block to convert the image data; a first conversion step of, when the block process determination unit determines the block process condition to be true, diffusing a gradation error for the entire target block to unconverted pixels outside the target block on the basis of the gradation value and the diffused gradation error for each pixel in the target block and converting image data for pixels in the target block at a time; and a second conversion step of determining whether or not to form a dot in the target block on the basis of the gradation value and the diffused gradation error for each pixel in the target block when the block process determination step determines the block process condition to be false, of converting image data for pixels in the target block while diffusing a gradation error for the pixel partition to the other unconverted pixels on the basis of the gradation value and the diffused gradation error for each pixel according to each pixel partition comprising grouped pixels in the target block when it is determined that a dot is to be formed in the target block, and of converting image data for pixels in the target block at a time while diffusing a gradation error for the entire target block to the other unconverted pixels outside the target block on the basis of the gradation value and the diffused gradation error for each pixel in the target block when it is determined that no dot is to be formed in the target block.
3. A computer-readable medium having an image data processing program stored thereon, the image data processing program allowing a computer to implement a function which inputs image data generated from an image represented in multiple gradations of dot matrix pixels, diffuses a gradation error for each pixel to the other unconverted pixels, and converts the input image data to image data represented by presence or absence of dot formation, and the image data processing program comprising program instructions for causing a computer to implement: a block process determination function of forming a block by grouping a specified number of neighboring pixels and determining whether or not a specified block process condition is satisfied on the basis of a gradation value for each pixel in a target block to convert the image data; a first conversion function of, when the block process determination function determines the block process condition to be true, diffusing a gradation error for the entire target block to unconverted pixels outside the target block on the basis of the gradation value and the diffused gradation error for each pixel in the target block and converting image data for pixels in the target block at a time; and a second conversion function of determining whether or not to form a dot in the target block on the basis of the gradation value and the diffused gradation error for each pixel in the target block when the block process determination function determines the block process condition to be false, for converting image data for pixels in the target block while diffusing a gradation error for the pixel partition to the other unconverted pixels on the basis of the gradation value and the diffused gradation error for each pixel according to each pixel partition comprising grouped pixels in the target block when it is determined that a dot is to be formed in the target block, and for converting image data for pixels in the target block at a time while diffusing a gradation error for the entire target block to the other unconverted pixels outside the target block on the basis of the gradation value and the diffused gradation error for each pixel in the target block when it is determined that no dot is to be formed in the target block.
4. An image data processing apparatus which inputs image data generated from an image represented in multiple gradations of dot matrix pixels, diffuses a gradation error for each pixel to the other unconverted pixels, and converts the input image data to image data represented by presence or absence of dot formation, the apparatus comprising: a block process determination unit for forming a block by grouping a specified number of neighboring pixels and determining whether or not a specified block process condition is satisfied on the basis of only a gradation value for each pixel in a target block to convert the image data; a first conversion unit for diffusing a gradation error for the entire target block to unconverted pixels outside the target block on the basis of the gradation value and the diffused gradation error for each pixel in the target block and converting image data for pixels in the target block at a time when the block process determination unit determines the block process condition to be true; and a second conversion unit for being able to convert image data for pixels in the target block while diffusing a gradation error for the pixel partition to the other unconverted pixels on the basis of the gradation value and the diffused gradation error for each pixel according to each pixel partition comprising grouped pixels in the target block when the block process determination unit determines the block process condition to be false.
5. An image data processing method which inputs image data generated from an image represented in multiple gradations of dot matrix pixels, diffuses a gradation error for each pixel to the other unconverted pixels, and converts the input image data to image data represented by presence or absence of dot formation, the apparatus comprising: a block process determination step of forming a block by grouping a specified number of neighboring pixels and determining whether or not a specified block process condition is satisfied on the basis of only a gradation value for each pixel in a target block to convert the image data; a first conversion step of, when the block process determination unit determines the block process condition to be true, diffusing a gradation error for the entire target block to unconverted pixels outside the target block on the basis of the gradation value and the diffused gradation error for each pixel in the target block and converting image data for pixels in the target block at a time; and a second conversion step for being able to convert image data for pixels in the target block while diffusing a gradation error for the pixel partition to the other unconverted pixels on the basis of the gradation value and the diffused gradation error for each pixel according to each pixel partition comprising grouped pixels in the target block when the block process determination step determines the block process condition to be false.
6. A computer-readable medium having an image data processing program stored thereon, the image data processing program allowing a computer to implement a function which inputs image data generated from an image represented in multiple gradations of dot matrix pixels, diffuses a gradation error for each pixel to the other unconverted pixels, and converts the input image data to image data represented by presence or absence of dot formation, the image data processing program including program instructions for causing a computer to implement: a block process determination function of forming a block by grouping a specified number of neighboring pixels and determining whether or not a specified block process condition is satisfied on the basis of only a gradation value for each pixel in a target block to convert the image data; a first conversion function of, when the block process determination function determines the block process condition to be true, diffusing a gradation error for the entire target block to unconverted pixels outside the target block on the basis of the gradation value and the diffused gradation error for each pixel in the target block and converting image data for pixels in the target block at a time; and a second conversion function of being able to convert image data for pixels in the target block while diffusing a gradation error for the pixel partition to the other unconverted pixels on the basis of the gradation value and the diffused gradation error for each pixel according to each pixel partition comprising grouped pixels in the target block when the block process determination function determines the block process condition to be false.
7. An image data processing apparatus to generate image data to be supplied to an image output apparatus which outputs an image at a specified resolution by inputting image data generated from an image represented in multiple gradations of dot matrix pixels and diffusing a gradation error for each pixel to the other unconverted pixels and representing image data by presence or absence of dot formation, the apparatus comprising: a resolution acquisition unit for obtaining the resolution; and a conversion unit for identifying a conversion partition comprising one or more neighboring pixels corresponding to the resolution obtained by the resolution acquisition unit and converting image data at a time by diffusing a gradation error for the entire target conversion partition to unconverted pixels outside the conversion partition on the basis of a gradation value and the diffused gradation error for each pixel in the target conversion partition for converting the image data.
8. The image data processing apparatus according to claim 7 , wherein the conversion unit comprises: a block process determination unit for forming a block comprising two or more neighboring pixels according to the resolution and determining whether or not a specified block process condition is satisfied on the basis of a gradation value for each pixel in a target block converting the image data; a first conversion unit for diffusing a gradation error for the entire target block to unconverted pixels outside the target block on the basis of the gradation value and the diffused gradation error for each pixel in the target block and converting image data for pixels in the target block at a time when the block process determination unit determines the block process condition to be true; and a second conversion unit for being able to convert image data for pixels in the target block while diffusing a gradation error for the pixel partition to the other unconverted pixels on the basis of the gradation value and the diffused gradation error for each pixel according to each pixel partition comprising grouped pixels in the target block when the block process determination unit determines the block process condition to be false.
9. An image data processing method of generating image data to be supplied to an image output apparatus which outputs an image at a specified resolution by inputting image data generated from an image represented in multiple gradations of dot matrix pixels and diffusing a gradation error for each pixel to the other unconverted pixels and representing image data by presence or absence of dot formation, the apparatus comprising: a resolution acquisition step of obtaining the resolution; and a conversion step of identifying a conversion partition comprising one or more neighboring pixels corresponding to the resolution obtained by the resolution acquisition step and converting image data at a time by diffusing a gradation error for the entire target conversion partition to unconverted pixels outside the conversion partition on the basis of a gradation value and the diffused gradation error for each pixel in the target conversion partition for converting the image data.
10. A computer-readable medium having an image data processing program stored thereon, the image data processing program allowing a computer to implement a function which generates image data to be supplied to an image output apparatus which outputs an image at a specified resolution by inputting image data generated from an image represented in multiple gradations of dot matrix pixels and diffusing a gradation error for each pixel to the other unconverted pixels and representing image data by presence or absence of dot formation, the image data processing program including program instructions for causing a computer to implement: a resolution acquisition function of obtaining the resolution; and a conversion function of identifying a conversion partition comprising one or more neighboring pixels corresponding to the resolution obtained by the resolution acquisition function and converting image data at a time by diffusing a gradation error for the entire target conversion partition to unconverted pixels outside the conversion partition on the basis of a gradation value and the diffused gradation error for each pixel in the target conversion partition for converting the image data.
11. An image data processing apparatus which inputs image data generated from an image represented in multiple gradations of dot matrix pixels, diffuses a gradation error for each pixel to the other unconverted pixels, and generates image data for representing an output image from an image output apparatus according to presence or absence of dot formation, the apparatus comprising: an image quality setup unit for accepting input of image quality setup information about image quality setting of an image output from the image output apparatus; and a conversion unit for identifying a conversion partition comprising one or more neighboring pixels corresponding to the input image quality setup information and converting image data at a time by diffusing a gradation error for the entire target conversion partition to unconverted pixels outside the conversion partition on the basis of a gradation value and the diffused gradation error for each pixel in the target conversion partition for converting the image data.
12. The image data processing apparatus according to claim 11 , wherein the image output apparatus is provided with a resolution acquisition unit for outputting an image at a specified resolution and obtaining the resolution; and the conversion unit configures the conversion partition comprising one or more neighboring pixels in accordance with the obtained resolution so that an area on the output image is smaller than or equal to the image as the resolution increases.
13. The image data processing apparatus according to claim 11 , wherein the conversion unit comprises: a determination unit for forming a block comprising two or more neighboring pixels and determining whether or not a specified block process condition is satisfied on the basis of a gradation value for each pixel in a target block converting the image data; a first conversion unit for assuming the target block to be the target conversion partition and converting the image data for the entire target block at a time when the determination unit determines the block process condition to be true; and a second conversion unit for being able to convert image data for pixels in the target block while using a pixel partition comprising grouped pixels in the target block as the conversion partition and diffusing a gradation error for the pixel partition to the other unconverted pixels on the basis of the gradation value and the diffused gradation error for each pixel when the block process determination unit determines the block process condition to be false.
14. An image data processing method of inputting image data generated from an image represented in multiple gradations of dot matrix pixels, diffusing a gradation error for each pixel to the other unconverted pixels, and generating image data for representing an output image from an image output apparatus according to presence or absence of dot formation, the method comprising: an image quality setup step of accepting input of image quality setup information about image quality setting of an image output from the image output apparatus; and a conversion step of identifying a conversion partition comprising one or more neighboring pixels corresponding to the input image quality setup information and converting image data at a time by diffusing a gradation error for the entire target conversion partition to unconverted pixels outside the conversion partition on the basis of a gradation value and the diffused gradation error for each pixel in the target conversion partition for converting the image data.
15. A computer-readable medium having an image data processing program stored thereon, the image data processing program allowing a computer to implement a function which generates image data for representing an output image from an image output apparatus according to presence or absence of dot formation by inputting image data generated from an image represented in multiple gradations of dot matrix pixels and diffusing a gradation error for each pixel to the other unconverted pixels, the image data processing program including program instructions for causing a computer to implement: an image quality setup function of accepting input of image quality setup information about image quality setting of an image output from the image output apparatus; and a conversion function of identifying a conversion partition comprising one or more neighboring pixels corresponding to the input image quality setup information and converting image data at a time by diffusing a gradation error for the entire target conversion partition to unconverted pixels outside the conversion partition on the basis of a gradation value and the diffused gradation error for each pixel in the target conversion partition for converting the image data.
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January 15, 2003
September 11, 2007
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